Headlamp adjuster mechanisms to adjust the vertical aim of vehicle headlamps are well known. Such mechanisms generally comprise an adjuster screw, extending toward the rear of the headlamp, the adjuster screw rotatably engaging a fixed member and being threaded through the headlamp reflector or, more commonly, through an insert attached to the reflector and the reflector is pivotally mounted to the headlamp. Rotation of the adjuster screw causes the reflector to move along the adjuster screw, pivoting with respect to the headlamp, to tilt up or down, adjusting the aim of the headlamp.
Known headlamp adjuster mechanisms generally fall into either the ninety degree adjuster category or the one hundred and eighty degree adjuster category. Ninety degree adjusters are those in which the adjustment is effected by rotating a member which extends at ninety degrees to the adjuster screw and engages the adjuster screw through a gear system such that rotation of the member rotates the adjuster screw. Examples include mechanisms wherein the user turns an adjuster rod, extending vertically upward from the adjuster screw, behind the headlamp assembly in the engine compartment of the vehicle.
Similarly, one hundred and eighty degree adjusters include an adjusting member which extends from the headlamp towards the front of the vehicle, beside the headlamp, and rotation of this adjusting member causes rotation of the adjuster screw through a gear system.
While one hundred and eighty degree adjuster mechanisms are generally preferred, they do suffer from disadvantages. In particular, the adjusting member typically must be relatively long to reach from the adjuster screw at the rear of the headlamp to the front of the headlamp and thus the adjusting member can represent a relatively large proportion of the manufacturing cost of the headlamp adjuster mechanism and the weight of the adjusting member is always present on the vehicle, decreasing vehicle fuel economy, despite the fact that headlamps are generally adjusted very infrequently. Further, mounting the adjusting member to ensure that it will be operable over its expected lifetime, despite the harsh environment it is exposed to, and to prevent rattling or vibration of the adjusting member during operation of the vehicle, can be difficult to achieve. Also, during assembly of the headlamp it can be difficult to align the adjusting member with respect to the adjuster screw and headlamp housing.